Different variations of devices and methods for monitoring a sensor located in a vehicle are known.
A circuit arrangement for evaluating the signals from a yaw rate sensor is described in European Patent No. 0 751 888. For this purpose, the signals from the yaw rate sensor are supplied to a control unit. Signals from at least one sensor--in most cases, however, a plurality of sensors--which detects driving status-dependent quantities such as the steering wheel angle, wheel rotational speeds, transverse and longitudinal acceleration, etc. are also supplied to the control unit. Based on these signals, the control unit calculates a reference yaw rate and compares it to the yaw rate measured by a sensor. For this purpose, the difference between the reference yaw rate and the yaw rate measured by the yaw rate sensor is determined and compared to a preset threshold value. A status signal, which indicates whether the yaw rate sensor is in proper working order or is defective, is emitted, based on the result of this comparison. The reference yaw rate is determined as follows: using different mathematical models, various values for the yaw rate are determined on the basis of the further sensor signals. A reference yaw rate is determined by addition, based on these values, weighted by factors that are determined with the help of fuzzy logic. Determining the reference yaw rate using fuzzy logic involves a considerable amount of effort.
A device and a method for monitoring a yaw rate sensor, a transverse acceleration sensor, a steering angle sensor, and wheel speed sensors that are located in a vehicle are described in German Patent No. 196 36 443. Using mathematical models to which the sensor signal determined by the sensor is supplied, a yaw rate is determined for the yaw rate sensor, transverse acceleration sensor, steering angle sensor, and wheel speed sensors. A reference yaw rate is determined on the basis of these yaw rates determined for the different sensors. Using an inverted mathematical model for the various sensors, a sensor reference quantity is determined on the basis of this reference yaw rate. The individual sensors are monitored with the aid of this sensor reference quantity. This device and this method are used to simultaneously monitor multiple sensors provided in a vehicle. It is not possible, however, to monitor a single sensor.
A control device with an acceleration sensor and an error control unit for motor vehicles is described in German Patent No. 39 30 302. This control device includes a first acceleration sensor for detecting longitudinal accelerations and a second acceleration sensor, for example, for detecting transverse accelerations. The control device also includes a facility for recording the signals from the acceleration sensors and for deriving a data value on the basis of the two signals. The data value is compared to a preset comparison value in a further facility and an error in one of the sensor signals is detected. The data value is derived, for example, by adding up the acceleration signals or determined as the root of the sum of the squares of the acceleration signals. The use of a transverse acceleration quantity determined directly as a function of wheel speed quantities is not described.